id: Q09822
gene_symbol: cdc15
product_type: PROTEIN
status: DRAFT
taxon:
  id: NCBITaxon:284812
  label: Schizosaccharomyces pombe (strain 972 / ATCC 24843)
description: |-
  Cdc15 (SPAC20G8.05c) is the founding member of the PCH/F-BAR (Pombe Cdc15
  Homology) protein family and an essential membrane-cytoskeleton scaffolding
  protein required for cytokinesis in fission yeast. It has a three-part domain
  architecture: an N-terminal FCH/F-BAR membrane-binding module, a central
  intrinsically disordered region (IDR) that is uniquely essential and heavily
  phosphoregulated, and a C-terminal SH3 protein-interaction domain. Its core
  molecular role is to couple the plasma membrane to actomyosin contractile-ring
  components and regulators, thereby driving assembly, anchoring, and integrity
  of the contractile ring at the cell division site. The F-BAR domain binds
  membrane phospholipids and provides a protein-binding platform that directly
  recruits the formin Cdc12 (and type-I myosin Myo1), while the SH3 domain (partly
  redundant with the SH3 of the paralog Imp2) recruits ring-stabilizing proteins
  such as Pxl1 (paxillin) and Fic1. Cdc15 is hyperphosphorylated in interphase
  (localizing to cortical patches at cell tips) and becomes hypophosphorylated
  during mitosis/cytokinesis (relocalizing to the medial contractile ring);
  dephosphorylation (involving the Clp1/Cdc14-family phosphatase) promotes an
  assembly-competent open conformation, increased membrane binding, oligomerization,
  and phase separation, whereas multiple polarity kinases (Pom1, Kin1, Shk1/Pak1,
  Pck1) phosphorylate the IDR to antagonize condensation and ring assembly. Note
  that S. pombe Cdc15 is an F-BAR/SH3 scaffold and is NOT a protein kinase
  (unlike the unrelated budding-yeast Cdc15 of the Mitotic Exit Network).
existing_annotations:
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Cdc15 binds the plasma membrane via its F-BAR domain and acts at the
      cytoplasmic face of the plasma membrane, where it anchors the contractile
      ring. This localization is well supported and phosphoregulated.
    action: ACCEPT
    reason: Core localization for an F-BAR membrane-binding scaffold; consistent
      with phospholipid binding and membrane-anchor activity annotations.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: couple the plasma membrane to contractile-ring components
        and regulators
      reference_section_type: OTHER
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Cdc15 has a cytosolic pool, particularly in interphase, but its functionally
      relevant localizations are the cell tips (interphase) and the medial
      cortex/contractile ring (mitosis). The bare cytoplasm term is correct but
      uninformative relative to the specific cortical/ring localizations.
    action: KEEP_AS_NON_CORE
    reason: Generic compartment; subsumed by more specific cortical and division-site
      localizations that capture the functional sites of action.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Dephosphorylation correlates with relocalization from mainly
        cytosolic/interphase pools to the division site
      reference_section_type: OTHER
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Cdc15 accumulates at the medial cortex/cell division site during
      mitosis/cytokinesis, where it scaffolds the contractile ring. This is a
      core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function; the contractile ring assembles and
      constricts at the cell division site.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: In **mitosis/cytokinesis**, it accumulates at the **medial
        cortex/contractile ring**
      reference_section_type: OTHER
- term:
    id: GO:0007010
    label: cytoskeleton organization
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Cdc15 organizes the actomyosin contractile ring, a cytoskeletal structure.
      The specific term mitotic actomyosin contractile ring assembly (GO:1903475)
      captures this more precisely; the generic parent is retained as non-core.
    action: KEEP_AS_NON_CORE
    reason: General parent process; the specific contractile-ring assembly term is
      the core biological process.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: assembly, anchoring, and integrity of the actomyosin
        contractile ring
      reference_section_type: OTHER
- term:
    id: GO:0005543
    label: phospholipid binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      The Cdc15 F-BAR domain binds membrane phospholipids; its concave surface
      engages the membrane while the opposite surface binds protein ligands. This
      is a core molecular function of the F-BAR scaffold.
    action: ACCEPT
    reason: Direct membrane phospholipid binding by the F-BAR domain is a core
      molecular function underlying membrane anchoring.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: The **concave F-BAR surface** binds membranes, while the
        **opposite surface** binds protein ligands
      reference_section_type: OTHER
- term:
    id: GO:0120104
    label: mitotic actomyosin contractile ring, proximal layer
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Nanoscale architecture studies place Cdc15 in the membrane-proximal layer of
      the contractile ring, consistent with its role linking the ring to the
      plasma membrane. This is a precise and appropriate localization.
    action: ACCEPT
    reason: Cdc15 is a membrane-proximal ring component that anchors the ring to
      the plasma membrane.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: physically linking the ring to the plasma membrane
      reference_section_type: OTHER
- term:
    id: GO:0005543
    label: phospholipid binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: |-
      F-BAR-mediated phospholipid binding is supported experimentally and by domain
      inference; consistent with the IBA annotation to the same term.
    action: ACCEPT
    reason: Core molecular function; matches experimentally supported F-BAR
      membrane binding.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: a dimeric/oligomeric membrane-binding module
      reference_section_type: OTHER
- term:
    id: GO:0005856
    label: cytoskeleton
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: |-
      Cdc15 associates with the actomyosin contractile ring (a cytoskeletal
      structure). The specific contractile-ring CC terms (GO:0110085, GO:0120104)
      are more informative; the generic parent is non-core.
    action: KEEP_AS_NON_CORE
    reason: Overly general; specific contractile-ring localizations capture the
      functional site.
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: |-
      This is the central molecular function of Cdc15: it couples the plasma
      membrane to the actomyosin contractile ring, linking a cytoskeletal
      structure to the membrane via its F-BAR domain. Strongly supported across
      multiple lines of evidence.
    action: ACCEPT
    reason: Core molecular function of the F-BAR scaffold; membrane-cytoskeleton
      anchoring.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: couple the plasma membrane to contractile-ring components
        and regulators
      reference_section_type: OTHER
- term:
    id: GO:0120104
    label: mitotic actomyosin contractile ring, proximal layer
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: |-
      Cdc15 occupies the membrane-proximal layer of the contractile ring; consistent
      with the IBA and IDA annotations to this term.
    action: ACCEPT
    reason: Core membrane-proximal ring localization.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: physically linking the ring to the plasma membrane
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: |-
      Cdc15 is an early, abundant contractile-ring component essential for ring
      assembly; it provides a membrane-associated scaffold that recruits and
      organizes the ring machinery (including the formin Cdc12). This is a core
      biological process.
    action: ACCEPT
    reason: Core biological process; Cdc15 drives contractile-ring assembly.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: early and abundant** contractile-ring component and is
        **essential for cytokinesis**
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:12939254
  review:
    summary: |-
      Cdc15 directly binds multiple ring proteins (formin Cdc12, type-I myosin
      Myo1, Pxl1, Fic1) via its F-BAR and SH3 domains, coordinating two F-actin
      nucleation pathways for ring formation. While the underlying interactions are
      real and important, the bare protein binding term is uninformative and is
      better captured by the membrane-anchor activity and specific recruitment
      annotations.
    action: MARK_AS_OVER_ANNOTATED
    reason: The bare protein binding term is uninformative; the specific
      scaffolding/recruitment functions are captured by GO:0106006 and the
      contractile-ring assembly terms.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: implicated as recruited via the F-BAR region in the prevailing
        model of medial F-actin nucleation factor recruitment
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19474789
  review:
    summary: |-
      Generic protein-binding annotation. Cdc15 relevant interactions (e.g., with
      polarity kinases and ring components) are better represented by specific
      molecular-function and process terms.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; superseded by specific functional terms.
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: EXP
  original_reference_id: PMID:15933715
  review:
    summary: |-
      Experimental support for Cdc15 acting as a membrane-cytoskeleton anchor at
      the division site; consistent with the core molecular function.
    action: ACCEPT
    reason: Core molecular function with experimental support.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: membrane–cytoskeleton scaffolding protein
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:35108037
  review:
    summary: |-
      This annotation reflects the direct Cdc15-Pxl1 (paxillin) interaction; Pxl1
      contains two Cdc15-binding motifs for robust recruitment to the ring. The
      specific interaction is captured by membrane-anchor/recruitment terms; the
      bare protein binding term is uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; the Pxl1 recruitment role is captured by
      the membrane-anchor and ring-assembly annotations.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: recruited via SH3 domains of Cdc15 and Imp2
      reference_section_type: OTHER
- term:
    id: GO:0061171
    label: establishment of bipolar cell polarity
  evidence_type: IMP
  original_reference_id: PMID:23093943
  review:
    summary: |-
      Cdc15 localizes to cell tips in interphase and cytokinesis imposes constraints
      on polarized growth (new-end take-off), but bipolar polarity establishment is
      a downstream/pleiotropic consequence rather than Cdc15 core cytokinetic
      scaffolding function.
    action: KEEP_AS_NON_CORE
    reason: Pleiotropic developmental/polarity process secondary to the core
      cytokinesis function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: cortical patches at the cell tips
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IPI
  original_reference_id: PMID:23093943
  review:
    summary: |-
      Membrane-anchor molecular function supported by interaction evidence;
      consistent with the core function of Cdc15.
    action: ACCEPT
    reason: Core molecular function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: couple the plasma membrane to contractile-ring components
        and regulators
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: EXP
  original_reference_id: PMID:32101481
  review:
    summary: |-
      Pom1 (a DYRK-family kinase) phosphorylates Cdc15 to drive it from the membrane,
      regulating the membrane-anchor function; the underlying anchor activity is core.
    action: ACCEPT
    reason: Core molecular function; phosphoregulation modulates membrane association.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: 'Multiple kinases contribute (Pom1, Kin1, Shk1/Pak1, Pck1)'
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: EXP
  original_reference_id: PMID:25428987
  review:
    summary: |-
      The Cdc15 and Imp2 SH3 domains cooperatively scaffold a network of ring
      proteins; the membrane-anchor activity is the core molecular function.
    action: ACCEPT
    reason: Core molecular function with experimental support.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: SH3 domains of Cdc15 and Imp2 cooperatively recruit Pxl1 and
        Fic1
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IMP
  original_reference_id: PMID:24127216
  review:
    summary: |-
      Cdc15-dependent recruitment of the formin Cdc12 (cooperating with For3) for
      ring assembly relies on the membrane-anchor scaffold function.
    action: ACCEPT
    reason: Core molecular function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Cdc15 directly binds Cdc12, and Cdc12 binding is
        phosphorylation-state dependent
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: EXP
  original_reference_id: PMID:33357436
  review:
    summary: |-
      Structural work shows opposite surfaces of the Cdc15 F-BAR create a membrane
      platform: the concave surface binds membrane, the opposite surface binds
      protein ligands (e.g., Cdc12). This directly demonstrates the membrane-anchor
      molecular function.
    action: ACCEPT
    reason: Core molecular function directly demonstrated structurally.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Cdc15 F-BAR domain contains a defined Cdc12-binding surface
        with micromolar affinity
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IDA
  original_reference_id: PMID:33357436
  review:
    summary: |-
      Direct assay support for the F-BAR membrane platform that coordinates
      cytoskeletal and signaling components; core molecular function.
    action: ACCEPT
    reason: Core molecular function directly assayed.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: The **concave F-BAR surface** binds membranes, while the
        **opposite surface** binds protein ligands
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IMP
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Mutational analysis shows oligomerization (not membrane bending) underlies
      Cdc15 function; the membrane-anchor activity remains core. F-BAR oligomerization
      is important for stable ring architecture.
    action: ACCEPT
    reason: Core molecular function; oligomerization-dependent membrane anchoring.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: F-BAR oligomerization is important for stable ring architecture
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: EXP
  original_reference_id: PMID:25688133
  review:
    summary: |-
      The F-BAR Cdc15 promotes ring formation through direct recruitment of the
      formin Cdc12 to the membrane; this depends on the membrane-anchor scaffold
      function.
    action: ACCEPT
    reason: Core molecular function with experimental support.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: recruiting factors (including the formin Cdc12) and physically
        linking the ring to the plasma membrane
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24790095
  review:
    summary: |-
      Reflects an interaction detected in studies of Blt1 (a ring/node component).
      Generic protein binding is uninformative relative to the specific
      scaffolding functions.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; superseded by specific functional terms.
- term:
    id: GO:0032178
    label: medial membrane band
  evidence_type: IDA
  original_reference_id: PMID:31276301
  review:
    summary: |-
      Cdc15 localizes to the medial membrane band at the division site, consistent
      with its membrane-proximal contractile-ring localization.
    action: ACCEPT
    reason: Core medial division-site localization.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: it accumulates at the **medial cortex/contractile ring**
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23615450
  review:
    summary: |-
      Reflects interaction with the IQGAP Rng2, a node/ring component detected in
      the Cdc15 phosphorylation-dependent interactome. Generic protein binding is
      uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; the Rng2 interaction is captured by the
      ring-assembly and anchor annotations.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Additional partners detected in a phosphorylation-dependent
        interactome context include **Cyk3** and **Rng2**
      reference_section_type: OTHER
- term:
    id: GO:0071341
    label: medial cortical node
  evidence_type: IDA
  original_reference_id: PMID:16864655
  review:
    summary: |-
      The contractile ring assembles from a broad band of medial cortical nodes;
      Cdc15 is a node/ring component. This is a core localization.
    action: ACCEPT
    reason: Core localization; nodes are precursors of the contractile ring.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: helps recruit and organize ring machinery
      reference_section_type: OTHER
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:16864655
  review:
    summary: |-
      Cdc15 is a bona fide component of the mitotic actomyosin contractile ring;
      directly observed at the ring. Core localization.
    action: ACCEPT
    reason: Core localization; Cdc15 is an integral contractile-ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: early and abundant** contractile-ring component
      reference_section_type: OTHER
- term:
    id: GO:0005543
    label: phospholipid binding
  evidence_type: IDA
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Direct assay support for Cdc15 F-BAR phospholipid binding; core molecular
      function.
    action: ACCEPT
    reason: Core molecular function directly assayed.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: a dimeric/oligomeric membrane-binding module
      reference_section_type: OTHER
- term:
    id: GO:0009898
    label: cytoplasmic side of plasma membrane
  evidence_type: IDA
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Cdc15 acts on the cytoplasmic (inner) face of the plasma membrane, where its
      F-BAR domain binds the membrane and anchors the ring. Precise and core
      localization.
    action: ACCEPT
    reason: Core localization; the F-BAR binds the inner leaflet of the plasma
      membrane.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: The **concave F-BAR surface** binds membranes
      reference_section_type: OTHER
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: IDA
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Direct observation of Cdc15 at the cell division site; core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: scaffolding at the division site
      reference_section_type: OTHER
- term:
    id: GO:0097753
    label: membrane bending
  evidence_type: IMP
  original_reference_id: PMID:26702831
  negated: true
  review:
    summary: |-
      This is a NOT annotation. Although F-BAR proteins are canonically associated
      with membrane curvature, the study demonstrates that oligomerization, NOT
      membrane bending, underlies Cdc15 function in cytokinesis. The negation is
      therefore correct: Cdc15 does not require membrane-bending activity for its
      essential cytokinetic role.
    action: ACCEPT
    reason: The negation is correct and informative; oligomerization rather than
      membrane bending underlies Cdc15 function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: F-BAR oligomerization is important for stable ring architecture
      reference_section_type: OTHER
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:16687577
  review:
    summary: |-
      Cell-cycle-dependent imaging directly places Cdc15 at the actomyosin ring
      during mitosis; core localization.
    action: ACCEPT
    reason: Core localization; integral contractile-ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial contractile ring during mitosis
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IGI
  original_reference_id: PMID:16687577
  review:
    summary: |-
      Genetic interaction evidence that Cdc15 is required for actomyosin ring
      formation; core biological process.
    action: ACCEPT
    reason: Core biological process; Cdc15 is essential for ring assembly.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: early and abundant** contractile-ring component and is
        **essential for cytokinesis**
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IMP
  original_reference_id: PMID:25688133
  review:
    summary: |-
      Cdc15 promotes ring formation through direct recruitment of the formin Cdc12;
      core biological process.
    action: ACCEPT
    reason: Core biological process with mutant-phenotype support.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: recruiting factors (including the formin Cdc12) and physically
        linking the ring to the plasma membrane
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IPI
  original_reference_id: PMID:29343550
  review:
    summary: |-
      Cdk1-dependent phosphoinhibition of the formin-F-BAR (Cdc12-Cdc15) interaction
      regulates ring formation; the underlying anchor/recruitment activity is core.
    action: ACCEPT
    reason: Core molecular function; phosphoregulated Cdc12 recruitment.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: hypophosphorylated Cdc15 binds; hyperphosphorylated binds poorly
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: EXP
  original_reference_id: PMID:29343550
  review:
    summary: |-
      Phosphoregulation of the Cdc12-Cdc15 interaction opposes contractile-ring
      formation; core biological process.
    action: ACCEPT
    reason: Core biological process.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Cdc12 binding is phosphorylation-state dependent
      reference_section_type: OTHER
- term:
    id: GO:0071341
    label: medial cortical node
  evidence_type: IDA
  original_reference_id: PMID:21422229
  review:
    summary: |-
      Cdc15 is part of precursor nodes that assemble into the contractile ring;
      core localization.
    action: ACCEPT
    reason: Core localization; nodes are ring precursors.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: helps recruit and organize ring machinery
      reference_section_type: OTHER
- term:
    id: GO:0030479
    label: actin cortical patch
  evidence_type: IDA
  original_reference_id: PMID:21885283
  review:
    summary: |-
      Cdc15 (with Bzz1) has a distinct role in actin polymerization at sites of
      endocytosis, localizing to actin cortical patches. This endocytic role is a
      genuine but non-core moonlighting function relative to its essential
      cytokinetic scaffolding.
    action: KEEP_AS_NON_CORE
    reason: Endocytosis-associated cortical-patch localization is a secondary
      function distinct from the core cytokinetic role.
- term:
    id: GO:0072583
    label: clathrin-dependent endocytosis
  evidence_type: IMP
  original_reference_id: PMID:21885283
  review:
    summary: |-
      Cdc15 contributes to actin polymerization at endocytic sites alongside the
      F-BAR protein Bzz1. This is a non-core function distinct from the essential
      cytokinetic scaffolding role.
    action: KEEP_AS_NON_CORE
    reason: Moonlighting endocytic function; not the core cytokinesis role.
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:21885283
  review:
    summary: |-
      Cdc15 directly observed at the contractile ring; core localization.
    action: ACCEPT
    reason: Core localization; integral ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial cortex/contractile ring
      reference_section_type: OTHER
- term:
    id: GO:0120104
    label: mitotic actomyosin contractile ring, proximal layer
  evidence_type: IDA
  original_reference_id: PMID:28914606
  review:
    summary: |-
      Nanoscale architecture analysis directly places Cdc15 in the membrane-proximal
      layer of the contractile ring; core localization.
    action: ACCEPT
    reason: Core membrane-proximal ring localization, directly observed.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: physically linking the ring to the plasma membrane
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IPI
  original_reference_id: PMID:19139265
  review:
    summary: |-
      The SH3 domains of two PCH family members (Cdc15 and Imp2) cooperate in
      assembling the contractile ring; the membrane-anchor activity is core.
    action: ACCEPT
    reason: Core molecular function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: partly **redundant with the SH3 domain of the paralog Imp2**
      reference_section_type: OTHER
- term:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  evidence_type: IMP
  original_reference_id: PMID:28784611
  review:
    summary: |-
      Phosphoinositide-mediated ring anchoring resists perpendicular forces to
      promote medial cytokinesis; the Cdc15 membrane-anchor activity is central to
      this mechanical anchoring.
    action: ACCEPT
    reason: Core molecular function; mechanical anchoring of the ring to the membrane.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Coupling membrane remodeling and cytoskeletal force generation
      reference_section_type: OTHER
- term:
    id: GO:0030479
    label: actin cortical patch
  evidence_type: IDA
  original_reference_id: PMID:14602073
  review:
    summary: |-
      Cdc15 observed at actin cortical patches; consistent with its endocytosis-
      associated localization. Non-core relative to the cytokinetic scaffold role.
    action: KEEP_AS_NON_CORE
    reason: Cortical-patch localization tied to the non-core endocytic function.
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:14602073
  review:
    summary: |-
      Spatiotemporal pathway analysis directly places Cdc15 at the contractile ring
      during assembly and constriction; core localization.
    action: ACCEPT
    reason: Core localization; integral ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: early and abundant** contractile-ring component
      reference_section_type: OTHER
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:18378776
  review:
    summary: |-
      Cdc15 at the contractile ring in the context of Clp1/Cdc14 phosphatase and
      Mid1; core localization.
    action: ACCEPT
    reason: Core localization; integral ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial contractile ring during mitosis
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Generic protein-binding annotation arising from interaction assays in the
      oligomerization study. The functional interactions are captured by the
      membrane-anchor and ring annotations.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; superseded by specific functional terms.
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IMP
  original_reference_id: PMID:26702831
  review:
    summary: |-
      Cdc15 oligomerization underlies its function in contractile-ring assembly;
      core biological process.
    action: ACCEPT
    reason: Core biological process.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: F-BAR oligomerization is important for stable ring architecture
      reference_section_type: OTHER
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:24790095
  review:
    summary: |-
      Cdc15 at the contractile ring in the context of Blt1 characterization; core
      localization.
    action: ACCEPT
    reason: Core localization; integral ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial cortex/contractile ring
      reference_section_type: OTHER
- term:
    id: GO:0043332
    label: mating projection tip
  evidence_type: IDA
  original_reference_id: PMID:25825517
  review:
    summary: |-
      During mating/cell fusion, a formin-nucleated actin aster concentrates cell
      wall hydrolases; Cdc15 localizes to the mating projection (fusion focus) tip.
      This is a non-core, context-specific localization distinct from the core
      cytokinetic role.
    action: KEEP_AS_NON_CORE
    reason: Mating/fusion-specific localization; not the core cytokinesis function.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IDA
  original_reference_id: PMID:7634333
  review:
    summary: |-
      Early characterization of the cdc15 gene noted a cytoplasmic pool. The
      functionally relevant localizations are the cortical/division-site pools.
    action: KEEP_AS_NON_CORE
    reason: Generic compartment; subsumed by specific cortical/ring localizations.
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: IDA
  original_reference_id: PMID:7634333
  review:
    summary: |-
      The original cdc15 study showed it is key to F-actin reorganization at mitosis
      at the division site; core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: scaffolding at the division site
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IMP
  original_reference_id: PMID:7634333
  review:
    summary: |-
      Loss of cdc15 disrupts F-actin reorganization required for ring formation at
      mitosis; core biological process.
    action: ACCEPT
    reason: Core biological process; founding evidence for the Cdc15 cytokinetic role.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: essential for cytokinesis
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:25428987
  review:
    summary: |-
      Generic protein-binding annotation from the SH3-domain interaction-network
      study; the specific SH3-mediated recruitment of Pxl1/Fic1 is captured by the
      anchor and ring-assembly annotations.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; superseded by specific functional terms.
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: IDA
  original_reference_id: PMID:25428987
  review:
    summary: |-
      Cdc15 at the cell division site in the SH3-network study; core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: scaffolding at the division site
      reference_section_type: OTHER
- term:
    id: GO:0110085
    label: mitotic actomyosin contractile ring
  evidence_type: IDA
  original_reference_id: PMID:25428987
  review:
    summary: |-
      Cdc15 at the contractile ring; core localization.
    action: ACCEPT
    reason: Core localization; integral ring component.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial cortex/contractile ring
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IGI
  original_reference_id: PMID:25428987
  review:
    summary: |-
      Cdc15 and Imp2 SH3 domains redundantly ensure efficient cell division;
      combined loss abolishes ring formation. Core biological process.
    action: ACCEPT
    reason: Core biological process; SH3-mediated scaffolding ensures ring assembly.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: Combined loss of Cdc15/Imp2 SH3 functions abolishes ring formation
      reference_section_type: OTHER
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23966468
  review:
    summary: |-
      Reflects interaction in the Gef2-Nod1 cytokinesis-regulation network. Generic
      protein binding is uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative protein binding; superseded by specific functional terms.
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IMP
  original_reference_id: PMID:24127216
  review:
    summary: |-
      The formins Cdc12 and For3 cooperate during ring assembly downstream of
      Cdc15-mediated Cdc12 recruitment; core biological process.
    action: ACCEPT
    reason: Core biological process.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: recruiting factors (including the formin Cdc12)
      reference_section_type: OTHER
- term:
    id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  evidence_type: IMP
  original_reference_id: PMID:19139265
  review:
    summary: |-
      SH3-domain cooperation between Cdc15 and Imp2 drives contractile-ring
      assembly; core biological process.
    action: ACCEPT
    reason: Core biological process.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: SH3 domains of Cdc15 and Imp2 cooperatively recruit Pxl1 and
        Fic1
      reference_section_type: OTHER
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: HDA
  original_reference_id: PMID:16823372
  review:
    summary: |-
      High-throughput localization (ORFeome) places Cdc15 at the cell division site;
      consistent with directed studies. Core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function (corroborated by directed studies).
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: scaffolding at the division site
      reference_section_type: OTHER
- term:
    id: GO:0051286
    label: cell tip
  evidence_type: HDA
  original_reference_id: PMID:16823372
  review:
    summary: |-
      In interphase Cdc15 localizes to cortical patches at the cell tips; the
      high-throughput cell-tip localization is consistent with directed imaging.
    action: ACCEPT
    reason: Core interphase localization at cell tips.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: cortical patches at the cell tips
      reference_section_type: OTHER
- term:
    id: GO:0032178
    label: medial membrane band
  evidence_type: IDA
  original_reference_id: PMID:15517003
  review:
    summary: |-
      Cdc15 organizes a sterol-rich membrane domain during cytokinesis, consistent
      with localization to the medial membrane band at the division site.
    action: ACCEPT
    reason: Core medial division-site membrane localization.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: medial cortex/contractile ring
      reference_section_type: OTHER
- term:
    id: GO:0032153
    label: cell division site
  evidence_type: IDA
  original_reference_id: PMID:9786952
  review:
    summary: |-
      Study of imp2 (the Cdc15 paralog) places Cdc15 at the actin ring/division
      site; core localization.
    action: ACCEPT
    reason: Core site of Cdc15 function.
    supported_by:
    - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
      supporting_text: scaffolding at the division site
      reference_section_type: OTHER
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: HDA
  original_reference_id: PMID:10759889
  review:
    summary: |-
      Large-scale GFP-fusion localization detected a cytoplasmic pool. Generic
      compartment; functionally relevant pools are cortical/division-site.
    action: KEEP_AS_NON_CORE
    reason: Generic compartment from high-throughput screen; subsumed by specific
      localizations.
references:
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: PMID:10759889
  title: Large-scale screening of intracellular protein localization in living fission
    yeast cells by the use of a GFP-fusion genomic DNA library.
  findings: []
- id: PMID:12939254
  title: The PCH family protein, Cdc15p, recruits two F-actin nucleation pathways
    to coordinate cytokinetic actin ring formation in Schizosaccharomyces pombe.
  findings: []
- id: PMID:14602073
  title: Spatial and temporal pathway for assembly and constriction of the contractile
    ring in fission yeast cytokinesis.
  findings: []
- id: PMID:15517003
  title: Organization of a sterol-rich membrane domain by cdc15p during cytokinesis
    in fission yeast.
  findings: []
- id: PMID:15933715
  title: Etd1p is a novel protein that links the SIN cascade with cytokinesis.
  findings: []
- id: PMID:16687577
  title: Cell cycle-dependent roles for the FCH-domain protein Cdc15p in formation
    of the actomyosin ring in Schizosaccharomyces pombe.
  findings: []
- id: PMID:16823372
  title: ORFeome cloning and global analysis of protein localization in the fission
    yeast Schizosaccharomyces pombe.
  findings: []
- id: PMID:16864655
  title: Assembly of the cytokinetic contractile ring from a broad band of nodes in
    fission yeast.
  findings: []
- id: PMID:18378776
  title: The Clp1/Cdc14 phosphatase contributes to the robustness of cytokinesis by
    association with anillin-related Mid1.
  findings: []
- id: PMID:19139265
  title: The SH3 domains of two PCH family members cooperate in assembly of the Schizosaccharomyces
    pombe contractile ring.
  findings: []
- id: PMID:19474789
  title: A spatial gradient coordinates cell size and mitotic entry in fission yeast.
  findings: []
- id: PMID:21422229
  title: Assembly and architecture of precursor nodes during fission yeast cytokinesis.
  findings: []
- id: PMID:21885283
  title: Distinct roles for F-BAR proteins Cdc15p and Bzz1p in actin polymerization
    at sites of endocytosis in fission yeast.
  findings: []
- id: PMID:23093943
  title: Cytokinesis-based constraints on polarized cell growth in fission yeast.
  findings: []
- id: PMID:23615450
  title: Separate roles of IQGAP Rng2p in forming and constricting the Schizosaccharomyces
    pombe cytokinetic contractile ring.
  findings: []
- id: PMID:23966468
  title: Cooperation between Rho-GEF Gef2 and its binding partner Nod1 in the regulation
    of fission yeast cytokinesis.
  findings: []
- id: PMID:24127216
  title: The formins Cdc12 and For3 cooperate during contractile ring assembly in
    cytokinesis.
  findings: []
- id: PMID:24790095
  title: Characterization of the roles of Blt1p in fission yeast cytokinesis.
  findings: []
- id: PMID:25428987
  title: The Cdc15 and Imp2 SH3 domains cooperatively scaffold a network of proteins
    that redundantly ensure efficient cell division in fission yeast.
  findings: []
- id: PMID:25688133
  title: The F-BAR Cdc15 promotes contractile ring formation through the direct recruitment
    of the formin Cdc12.
  findings: []
- id: PMID:25825517
  title: A formin-nucleated actin aster concentrates cell wall hydrolases for cell
    fusion in fission yeast.
  findings: []
- id: PMID:26702831
  title: Oligomerization but Not Membrane Bending Underlies the Function of Certain
    F-BAR Proteins in Cell Motility and Cytokinesis.
  findings: []
- id: PMID:28784611
  title: Phosphoinositide-mediated ring anchoring resists perpendicular forces to
    promote medial cytokinesis.
  findings: []
- id: PMID:28914606
  title: Nanoscale architecture of the Schizosaccharomyces pombe contractile ring.
  findings: []
- id: PMID:29343550
  title: Cdk1-dependent phosphoinhibition of a formin-F-BAR interaction opposes cytokinetic
    contractile ring formation.
  findings: []
- id: PMID:31276301
  title: A unique kinesin-like protein, Klp8, is involved in mitosis and cell morphology
    through microtubule stabilization.
  findings: []
- id: PMID:32101481
  title: DYRK kinase Pom1 drives F-BAR protein Cdc15 from the membrane to promote
    medial division.
  findings: []
- id: PMID:33357436
  title: Opposite Surfaces of the Cdc15 F-BAR Domain Create a Membrane Platform That
    Coordinates Cytoskeletal and Signaling Components for Cytokinesis.
  findings: []
- id: PMID:35108037
  title: Fission yeast paxillin contains two Cdc15 binding motifs for robust recruitment
    to the cytokinetic ring.
  findings: []
- id: PMID:7634333
  title: The S. pombe cdc15 gene is a key element in the reorganization of F-actin
    at mitosis.
  findings: []
- id: PMID:9786952
  title: imp2, a new component of the actin ring in the fission yeast Schizosaccharomyces
    pombe.
  findings: []
- id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
  title: Falcon deep research report on S. pombe cdc15
  findings:
  - statement: |
      Cdc15 is an essential cytokinetic scaffold with an N-terminal FCH/F-BAR
      module and a C-terminal SH3 domain, localizing to cell tips in interphase
      and the medial contractile ring during mitosis.
    supporting_text: |-
      The *S. pombe* protein studied in the primary cytokinesis literature is consistently named **Cdc15/Cdc15p**, described as an **essential cytokinetic scaffold** with an **N-terminal FCH/F-BAR module and a C-terminal SH3 domain**, localizing to **cell tips in interphase** and the **medial contractile ring during mitosis**
    reference_section_type: OTHER
  - statement: |
      The defining molecular role of Cdc15 is to couple the plasma membrane to
      contractile-ring components and regulators, organizing proteins needed to
      build and stabilize the ring.
    supporting_text: |-
      Its defining molecular role is to **couple the plasma membrane to contractile-ring components and regulators**, organizing proteins needed to build and stabilize the ring and coordinate furrow ingression/septation
    reference_section_type: OTHER
  - statement: |
      Cdc15 has a three-part architecture: an N-terminal FCH/F-BAR membrane-binding
      domain (platform for recruiting factors including formin Cdc12), a central
      intrinsically disordered region that is uniquely essential and the major
      substrate for multisite phosphorylation, and a C-terminal SH3 domain.
    supporting_text: |-
      - **N-terminal FCH/F-BAR domain**: a dimeric/oligomeric membrane-binding module that acts as a platform for recruiting factors (including the formin Cdc12) and physically linking the ring to the plasma membrane
    reference_section_type: OTHER
  - statement: |
      The central IDR is uniquely essential and cannot be replaced by the Imp2 IDR;
      it is the major substrate for multisite phosphorylation controlling
      conformational state and assembly behavior.
    supporting_text: |-
      a regulatory and interaction module that is **uniquely essential** in Cdc15 (cannot be replaced by the Imp2 IDR) and is the major substrate for multisite phosphorylation controlling conformational state and assembly behavior
    reference_section_type: OTHER
  - statement: |
      The C-terminal SH3 domain recruits ring proteins (notably Fic1 and Pxl1) and
      is partly redundant with the SH3 domain of the paralog Imp2.
    supporting_text: |-
      a protein–protein interaction module that recruits specific ring proteins (notably Fic1 and Pxl1) and contributes to ring integrity; it is partly **redundant with the SH3 domain of the paralog Imp2**
    reference_section_type: OTHER
  - statement: |
      The Cdc15 F-BAR domain binds the formin Cdc12 with a Kd of approximately 5
      micromolar (ITC) at a stoichiometry of one peptide per Cdc15 dimer; Cdc12
      binding is phosphorylation-state dependent (hypophosphorylated binds well).
    supporting_text: |-
      Cdc15 directly binds Cdc12, and Cdc12 binding is phosphorylation-state dependent (hypophosphorylated Cdc15 binds; hyperphosphorylated binds poorly)
    reference_section_type: OTHER
  - statement: |
      Cdc15 is hyperphosphorylated in interphase and becomes hypophosphorylated
      during division; dephosphorylation (involving the Clp1/Cdc14-like phosphatase)
      promotes cortical/medial localization, oligomerization, and membrane binding.
    supporting_text: |-
      Cdc15 is **hyperphosphorylated in interphase** and becomes **hypophosphorylated during division**
    reference_section_type: OTHER
  - statement: |
      Multiple polarity kinases (Pom1, Kin1, Shk1/Pak1, Pck1) phosphorylate the IDR;
      phosphorylation inhibits Cdc15 liquid-liquid phase separation and antagonizes
      cytokinetic ring assembly, whereas dephosphorylated Cdc15 forms droplets in
      vitro and PM-bound condensates in cells.
    supporting_text: |-
      **Dephosphorylated Cdc15 forms droplets in vitro**, while phosphorylation (e.g., by Pom1) inhibits droplet formation
    reference_section_type: OTHER
  - statement: |
      The membrane-binding concave F-BAR surface and the opposite protein-binding
      surface create a membrane platform; F-BAR oligomerization (not membrane
      bending) is important for stable ring architecture.
    supporting_text: |-
      The **concave F-BAR surface** binds membranes, while the **opposite surface** binds protein ligands such as **Cdc12** and **Pxl1**, creating a membrane platform that coordinates cytoskeletal and signaling components. F-BAR oligomerization is important for stable ring architecture
    reference_section_type: OTHER
  - statement: |
      S. pombe Cdc15 is an F-BAR/SH3 scaffold, NOT a protein kinase, and should not
      be confused with budding yeast Cdc15 (a Mitotic Exit Network kinase).
    supporting_text: |-
      do not confuse this target with **budding yeast Cdc15**, which is a **protein kinase** in the Mitotic Exit Network (MEN). The *S. pombe* Cdc15 described here is an **F-BAR/SH3 scaffold**, not a kinase
    reference_section_type: OTHER
core_functions:
- description: |-
    Cdc15 functions as a membrane-cytoskeleton anchor: its F-BAR domain binds the
    cytoplasmic face of the plasma membrane and couples it to the actomyosin
    contractile ring, providing a membrane-attached scaffold that recruits and
    organizes ring components (notably the formin Cdc12, type-I myosin Myo1, and
    the SH3-recruited stabilizers Pxl1 and Fic1) during cytokinesis.
  molecular_function:
    id: GO:0106006
    label: cytoskeletal protein-membrane anchor activity
  directly_involved_in:
  - id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  locations:
  - id: GO:0110085
    label: mitotic actomyosin contractile ring
  - id: GO:0009898
    label: cytoplasmic side of plasma membrane
  - id: GO:0032153
    label: cell division site
  supported_by:
  - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
    supporting_text: couple the plasma membrane to contractile-ring components and
      regulators
    reference_section_type: OTHER
  - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
    supporting_text: Cdc15 F-BAR domain contains a defined Cdc12-binding surface with
      micromolar affinity
    reference_section_type: OTHER
- description: |-
    The Cdc15 F-BAR domain binds membrane phospholipids (concave surface), an
    activity essential for anchoring the contractile ring to the inner leaflet of
    the plasma membrane; this membrane binding is enhanced by dephosphorylation of
    the central IDR during mitosis.
  molecular_function:
    id: GO:0005543
    label: phospholipid binding
  directly_involved_in:
  - id: GO:1903475
    label: mitotic actomyosin contractile ring assembly
  locations:
  - id: GO:0009898
    label: cytoplasmic side of plasma membrane
  supported_by:
  - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
    supporting_text: The **concave F-BAR surface** binds membranes, while the
      **opposite surface** binds protein ligands
    reference_section_type: OTHER
  - reference_id: file:SCHPO/cdc15/cdc15-deep-research-falcon.md
    supporting_text: a dimeric/oligomeric membrane-binding module
    reference_section_type: OTHER
suggested_questions:
- question: |-
    What is the precise in vivo contribution of Cdc15 liquid-liquid phase
    separation (condensate formation) versus classical oligomerization to
    contractile-ring assembly and stability?
- question: |-
    How is the combinatorial multisite phosphorylation code (Pom1, Kin1,
    Shk1/Pak1, Pck1) integrated to set the threshold for the Cdc15 closed-to-open
    conformational switch at mitotic onset?
suggested_experiments:
- description: |-
    Use phosphomutant and IDR-deletion alleles combined with live-cell imaging and
    quantitative FRAP to measure how Cdc15 condensation/oligomerization state
    controls the recruitment dynamics of Cdc12, Myo1, Pxl1, and Fic1 at the ring.
- description: |-
    Reconstitute Cdc15 F-BAR on supported lipid bilayers with purified Cdc12 and
    Pxl1 peptides to quantify how phosphorylation state tunes simultaneous membrane
    binding and partner recruitment (membrane-platform function) in vitro.